Pressure accumulator



Jan. 7, 1969 E. M. GREER 3,420,273

PRESSURE ACCUMULATOR Filed Nov. 30, 1965 Sheet 4 of 2 INVENTOR.

Jan. 7, 1969 E. M. GREER 3,420,273-

I PRESSURE ACCUMULATO'R v Filed Nov. 30, 1965 sheet 2 INVENTOR.

FDWAQQ M. *6/2679? United States Patent 2 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the art of pressure accumulators and particularly relates to an accumulator which has valve means in the liquid port thereof which provides for rapid flow of liquid into the accumulator for charging thereof and restricted flow of liquid out of the accumulator.

As conducive to an understanding of the invention it is noted that pressure accumulators are often used in systems to take up sudden surges in the pressure lines and to apply fluid under pressure to hydraulic actuators used in the system.

In order to take up such sudden surges of pressure, the accumulators generally have a relatively large liquid port which provides unrestricted flow into the liquid chamber of the accumulator. Where the accumulator liquid port also permits unrestricted flow out of the liquid chamber and the accumulator is of the type having a flexible partition and more particularly a deformable bladder defining the separator between the gas and liquid chambers of the accumulator which are charged with gas and oil under pressure, if there should be a sudden large dififerential between the pressure inside and outside the accumulator, due to the higher pressure inside the accumulator, the bladder which is compressed, will expand rapidly.

As a result of such rapid expansion of the bladder, if the liquid port remains open, the unrestricted flow may cause the hydraulic actuator to efiect movement of the movable member which it controls at an excessive rate of speed with resultant mechanical failure.

It is accordingly among the objects of the invention to provide a pressure accumulator which has but few parts which may readily be assembled at relatively low cost and which will substantially instantaneously take up sudden pressure surges in the system, yet will provide fiow out of the accumulator at a relatively slow controlled rate regardless of the magnitude of the pressure differential inside and outside of the accumulator.

According to the invention, these objects are accomplished by the arrangement and combination of elements hereinafter described and more particularly recited in the claims.

In the accompanying drawings in which are shown one of various possible embodiments of the several features of the invention.

FIG. 1 is a longitudinal sectional view of an accumulator accordin g to the invention,

FIG. 2 is a longitudinal detail sectional view on an enlarged scale showing the oil port construction of the accumulator,

FIG. 2a is a fragmentary detail sectional view with parts broken away showing the valve member in closed position,

FIG. 3 is a top plan view of the valve member of the accumulator, and

FIG. 4 is a diagrammatic view showing a typical installation of the accumulator.

Referring now to the drawings, as shown in FIG. 1, the pressure accumulator illustratively comprises a substantially cylindrical container 11 of rigid material such as 3,420,273 Patented Jan. 7, 1969 steel or aluminum, capable of withstanding the pressure to which it is to be subjected in use.

The container 11 has one end closed as at 12 and a sleeve 13 is positioned in an axial opening 14 in such closed end. As is clearly shown, the inner end 15 of the sleeve has an outwardly extending annular flange 16 which rests on the periphery of opening 14, and the sleeve is secured in fixed position as by welding as at 17.

The bore 18 of the sleeve 13, which defines a port through which fluid may flow, has its inner end 19 beveled to define a valve seat.

Positioned in the mouth of the container 11 remote from the closed end 12 thereof, is a substantially cupshaped cover member 21 which has an annular groove 22 in the outer surface of the side wall 23 thereof. The portion 24 of the side wall 23 between groove 22 and the periphery or inner end 25 of the said side wall 23 is of reduced diameter so that the outer surface of said side Wall portion 24 will be spaced from the inner surface of the container wall when the cover member 21 is positioned therein.

The cover member 21 has a peripheral rim 28 rising from the outer surface 29 thereof. The central portion 31 of the cover member 21 presents a fiat surface 32 which is in a plane extending beyond the plane of the end 33 of rim 28 and the top surface of the cover member from the root end of rim 28 to the periphery of the central portion 31 is inclined upwardly as at 34.

Positioned in the container 11 is a deformable partition illustratively in the form of an elongated bladder 35 of rubber or similar material having like characteristics. The bladder 35 is closed at one end as at 36 and the mouth of the bladder has a pair of spaced inwardly extending beads 37 38.

The bead 37 is designed to be accommodated in the annular groove 22, and the bead 38 is designed to be positioned beneath the end 25 of the side wall 23 of the cover member.

When so mounted with the cover member 21 positioned in the container, the bead 37 will be compressed in the annular groove 22 to form a fluid seal and the head 38 will be retained beneath the end 25 of the side wall 23, the portion 30 of the bladder wall between the beads 37, 38 being under tension.

In order to retain the cover member 21 in the container the periphery of the mouth of the container 11 is bent inwardly as shown so that it extends over the end 33 of the rim 28 and the inner edge 39 of the periphery 40 is bent downwardly into the annular recess 41 defined by the inclined portion 34 of the outer surface of the cover member.

Secured to the central portion 31 of the cover member 21 as by screws 42 is a disc 43, the periphery 44 of which will rest on the periphery 40 of the mouth of the container 11 to retain the end 33 of the rim 28 against the undersurface of the periphery 40.

As is shown in FIG. 1, the bladder 35 is substantially frusto-conical in cross section with its side wall 45 being of greater diameter at the portion thereof adjacent the bead 38 than at the closed end 36 thereof. The bladder may be charged with a gas under pressure through a port 48 defined by an axial bore extending through the central portion 31 of the cover member 21 and through axial boss 49 depending from the undersurface of the cover member. The boss 49 has a suitable air valve 51 therein which is concealed by the disc 43.

Mounted on the closed end 36 of the bladder 35 is a valve member 52 in the form of a hollow button, preferably formed from thin steel or aluminum. The valve member is substantially frusto-conical in cross section with the smaller diameter portion or apex thereof having a guide recess 53 therein. The mouth of the valve member 52 has an inwardly extending flange or rim 54 which defines the top wall of the valve member and the inner periphery 55 of said rim 54 defines an opening axially aligned with the recess 53.

The side wall 56 of the valve member is adapted to move against the beveled seat 19 to prevent extrusion of the bladder through port 18.

As is shown in FIG. 2, the outer end 61 of bore 18 of sleeve 13 is internally threaded to receive the externally threaded end of a nipple 62. The nipple 62 has an outstanding annular flange 63 at its outer end designed to abut against the outer end 64 of sleeve 13 to limit the inward movement of the nipple. An annular groove 65 is positioned in the root end of the nipple to accommodate a seal ring 66 which will be compressed between the wall of groove 65 and the beveled inner surface 67 of bore 18 at the outer end thereof when the nipple is tightened to define a seal.

The bore 18 of sleeve 13 has an annular shoulder 68 formed therein to serve as a stop to limit the inward movement of a valve member 69, the inner end 71 of the nipple 62 limiting the outward movement of said valve member 69.

As is shown in FIGS. 2 and 3, the valve member is a disc of rigid material which has a central passageway 72 therethrough and a plurality of arcuate passageways 73 extending therethrough adjacent the periphery 74 of the valve member.

The passageway 72 is axially aligned with hte bore 18 of sleeve 13 and the arcuate passageways 73 are aligned with the inner end 71 of the nipple 62.

As shown in FIGS. 2 and 3, the width of annular shoulder 68 is substantially the same as the width of the portion 75 of valve member 69 between the outer periphery 76 of the arcuate passageways 73 and the outer periphery 74 of the valve member. Thus, when the portion 75 of the valve member 69 abuts against shoulder 68 there will be unrestricted flow through the arcuate passageways 73.

The width of the inner end 71 of nipple 62 is greater than that of the arcuate passageways 73 so that when the valve member 69 is seated against the end 71 of the nipple 62 the arcuate passageways 73 will be closed and there will be flow only through the central passageway 72.

As is shown in FIG. 2, the cross sectional area of the inner end 77 of the bore 78 of nipple 62 is slightly less than the total cross sectional area of the arcuate passageways 73 and central passageway 72. The area provided by the annular opening a between the inner end 71 of nipple 62 and the undersurface 79 of valve member 69 when it is seated on shoulder 68 together with the area of central passageway 72 is also slightly greater than the area of the inner end 77 of bore 78.

As a result of the foregoing, it is apparent that when the valve member 69 is seated on shoulder 68 there will be substantially unrestricted flow of fluid through the sleeve 13 into the accumulator and when the valve mem ber 69 is seated on the inner end 71 of nipple 62 the sole flow from the accumulator will be through the central passageway 72 and hence such outward flow will be a fraction of the inward flow.

Although the accumulator above described is suitable for a wide variety of applications, in which inward flow must be unrestricted and outward flow restricted, a typical application is shown in FIG. 4.

Thus, the accumulator is associated with a plow designed to provide furrows in a field.

As illustratively shown in FIG. 4, the plow has a main frame 81 which mounts a plurality of plow blades 82, only one of which is shown. Each plow blade 82 is pivotally mounted as at 83 to the undersurface of the frame 81. The plow blade is maintained in operative position by means of a hydraulic actuator 85 pivotally mounted at one end as at 86 to the frame and having its piston rod 87 pivotally connected to the plow blade as at 88.

When the piston 89 of the actuator is forced outwardly by the application of fluid under pressure applied to the port 91 of the actuator 85, the plow blade 82 will pivot in a clockwise direction limited by the abutment of a projection 92 on the upper portion of the blade against adjustment screw 93.

According to the invention, the port 91 is connected by line 94 to the nipple 62 of the accumulator and through one-way valve 95 to charging valve 96-.

In the operation of the system shown in FIG. 4 with the disc 43 (FIG. 1) removed, the chamber 60 defined by bladder 35 is charged with gas under pressure through the port defined by bore 18. As a result, the bladder 35 will expand, substantially filling the container 11 and the valve member 52 will move downwardly until it seats on the beveled end 19 of sleeve 13 thereby closing port 18 and preventing extrusion of the bladder therefrom.

At this time with the accumulator in vertical position, the valve member 69 due to its weight, will be seated on the inner end 71 of nipple 62.

A source of oil under pressure greater than that of the gas in bladder 35 is then applied through open valve 96 to charge the system. Such oil will flow past one-way valve 95, through line 94 into the port 91 of hydraulic actuator 85 to pivot the plow blade 82 in a clockwise direction limited by the abutment of projection 92 against screw 93. In addition, the oil under pressure will flow through the bore 78 of nipple 62 and react against the undersurface 79 of the valve member 69. As a result, the valve member 69 will quickly move inwardly until its peripheral portion abuts against annular shoulder 68.

This movement which is only a relatively/slight amount, will completely open the arcuate passageways 73 and the oil under pressure Will flow substantially unrestricted through the arcuate passageways 73 as well as through central passageway 72 to react against the valve member 52 carried by bladder 35 and quickly move the latter off its seat to permit charging of chamber 61' defined between the outer surface of bladder 35 and container 11.

As a result, the bladder 35 will be deformed further to compress the gas therein.

The accumulator is charged until the pressure has built up to an amount so as to enable the actuator to exert the desired force against plow blade 82 which depends upon the particular plow installation involved.

Thereupon, the valve 96 is closed and the plow is ready for operation.

When the plow is pulled through a field as by a tractor, due to the force exerted by the hydraulic actuator which is supplied by the charged accumulator, the plow blade will remain in the position shown in FIG. 4 to provide the desired plowing action.

If the plow blade should hit an underground obstruction such as a rock R, for example, a sudden force will be built up tending to rotate the plow blade in a counterclockwise direction about its mount 83. As a result, the piston 89 will be moved rearwardly causing a sudden surge of pressure in the oil in line 94. The oil which will be flowing at a high rate of speed will flow through nipple 62 of the accumulator and react against the undersurface 79 of valve member 69 so that the latter will be forced upward against its seat 68. As a result, there will be substantially unrestricted flow of oil through nipple 62 into the oil chamber 61 of the accumulator through arcuate passageways 73. This will immediately deform the bladder 35 to compress the gas therein to take up the sudden shock and permit such pivoting movement of the plow blade 82.

As the plow is further advanced, the blade 82 will ride over the obstruction and when this occurs the force exerted to move the piston 89 rearwardly will be suddenly released. As a result, there will be a sudden large differential between the pressure inside the accumulator and the pressure in the actuator.

Due to such pressure differential, the force exerted against the top surface 99 of the valve member 69 will be far greater than that exerted against the bottom surface 79 of such valve member so that the valve member 69 will rapidly be forced outwardly against the end surface 71 of the nipple 62. This will cause the arcuate passageways 73 to be closed so that the fluid will only be able to flow through the relatively small central passageway 72 into the line 94 and into port 91 of the hydraulic actuator. As a result of such restriction of flow from-the accumulator, the bladder 35 therein will expand relatively slowly so that the valve member 52 carried by the bladder 35 will remain spaced from the valve seat 19.

Since the fluid under pressure is fiowing into the hydraulic actuator at a relatively slow rate, the piston 89 of such actuator will move outwardly relatively slowly so that the plow blade 82 will be pivoted relatively slowly back into its normal operating position.

This is to be contrasted with a system in which a high rate of flow from the accumulator is provided as soon as the plow blade 82 moves away from the obstruction R and the force against the blade is suddenly eliminated. In such a situation, due to the unrestricted high rate of flow from the accumulator, the plow blade 82 would be rapidly forced toward its normal operating position. However, due to the resistance of the soil, and especially where the latter is hard, the plow blade would not move rapidly through the soil, and hence the plow frame 81 itself would move outwardly, causing extreme vibration and in addition the plow blade would ride on the top surface of the ground and hence the desired uninterrupted furrow which the plow blade is designed to form would be broken. This problem is of course enhanced when it is considered that the plow frame 81 normally carries a large number of plow blades, and if one or more of the plow blades should suddenly be released after being restrained by an obstruction, irregular impact would be caused to the plow frame with the resultant likelihood of breakage of pivotal connections and the equipment carried by the frame. However, with the accumulator above described, due to the restricted flow of fluid outwardly from the accumulator, the force exerted by the actuator against the plow will build up relatively slowly thereby preventing a sharp impact of the plow blade against the ground. Consequently, the plow frame will not be disturbed and the plow blade will move into the ground to the desired operating position.

With the accumulator above described which has relatively few moving parts and is not likely to become deranged, substantially unrestricted flow may be achieved into the accumulator, and restricted flow may be achieved out of the accumulator.

As many changes could be made in the above construction, and many apparently widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A pressure accumulator comprising a container of rigid material having two ports, one of said ports being axially aligned with said container, and defining a liquid port, a deformable bladder of elastic material secured in said container separating said two ports from each other, said bladder extending axially in said container and being closed at one end, said liquid port comprising a sleeve extending axially from said container, said sleeve defining a valve seat at its inner end, said bladder having a valve at its closed end, and axially aligned therewith and adapted to move against said seat to close said liquid port, a valve member comprising a relatively thick disc of rigid material slida'bly mounted in said sleeve, said sleeve having an internal annular shoulder against which the periphery of the inner surface of said disc abuts to restrict inward movement of said disc, a nipple secured in the outer end of said sleeve, the inner end of said nipple being longitudinally spaced from said annular shoulder, the outer surface of said disc abutting against the inner end of said nipple to restrict outward movement of said disc, said valve member having a passageway therethrough adjacent its periphery, said annular shoulder being of width to provide full clearance for the adjacent end of said passageway when the disc abuts thereagainst in its innermost position, said inner end of said nipple being of width to close the adjacent end of said passageway when said disc abuts thereagainst in its outermost position, the area defined by the inner end of the bore of the nipple being substantially equal to the annular area defined by the space between the undersurface of the disc and the inner end of the nipple when the disc abuts against said annular shoulder and substantially equal to the cross sectional area of said passageways.

2. A pressure accumulator comprising a container of rigid material having two ports, one of said ports being axially. aligned with said container, and defining a liquid port, a deformable bladder of elastic material secured in said container separating said two ports from each other, said bladder extending axially in said container and being closed at one end, said liquid port comprising a sleeve extending axially from said container, said sleeve defining a valve seat at its inner end, said bladder having a valve at its closed end, and axially aligned therewith and adapted to move against said seat to close said liquid port, a valve member comprising a relatively thick disc of rigid material having a plurality of openings therethrough adjacent the periphery thereof, said valve member being slidably mounted in said sleeve, said sleeve having an internal annular shoulder against which the periphery of the inner surface of the disc outwardly of said arcuate passageway abuts to restrict inward movement of said disc, a nipple secured in the outer end of said sleeve, and longitudinally spaced from said annular shoulder, the outer surface of said disc abutting against the inner end of said nipple to restrict outward movement of said disc, the width of said annular shoulder being substantially equal to the width of the annular portion of said disc outwardly of said annular passageways and the width of the inner end of said nipple being greater than the width of said annular passageways, said disc having an additional passageway comprising a central bore therethrough of smaller cross sectional area than said plurality of passageways, the diameter of the wall portion of said sleeve bore between the annular shoulder and the inner end of said nipple being only slightly larger than the diameter of said disc to provide sliding fit with little clearance and the thickness of said disc being a major portion of the length of said wall portion.

References Cited UNITED STATES PATENTS Re. 23,333 1/1951 Mercier 13830 1,398,859 11/1921 Hurtig et al. 172705 1,512,736 10/1924 Aldrich 13831 1,988,194 1/1935 Erlandsen 138--31 XR 2,379,779 7/1945 Ash 172605 2,604,118 7/1952 Greer 138-30 2,716,997 9/1955 Crookston 137513.3 X 2,731,038 1/1956 Purcell 138-30 2,801,592 8/1957 Barton 137513.3 X 2,816,572 12/1957 Pratt 137513.3 X 2,8 80,75 8 4/ 1959 Mercier 13 8--3 0 2,886,065 5/1959 Hershman 137513.3 X 3,140,729 7/1964 Mercier 137513.3 X

(Other references on following page) 7/1966 Mercier et al. 138-30 5/1967 Evans 172705 X HOUSTQN S. BELL, JR., Primary Examiner.

5 NELSON C. CUDDEBACK, Assistant Examiner.

US. Cl. X.R. 

